Sen. Dianne Feinstein (D-Calif.) offered a full-throated defense of the government's collection of data on billions of American phone calls, saying Wednesday that the National Security Agency’s practices have safeguarded the nation without trampling on civil liberties.

“What keeps me up at night, candidly, is another attack against the United States. And I see enough of the threat stream to know that is possible,” Feinstein said at a Pacific Council on International Policy dinner in Century City.

She pointed to a warning Wednesday about potential bombs hidden in the shoes of passengers on flights bound for the United States.

“But the way we prevent another attack – and this is tricky – is intelligence," she said. "You have to know what’s going to happen, because it’s too late otherwise.”

Feinstein’s firm support for the NSA’s tracking program has divided some of her most ardent backers, and in recent months her popularity in California has plunged to a historic low.

During the hourlong question-and-answer session, several people questioned Feinstein, chairwoman of the Senate Intelligence Committee, about the boundaries of intelligence gathering and about NSA contractor Edward Snowden, who used his position to collect classified information about NSA activities that he has since made public.

Snowden, Feinstein said, had other options to serve as a whistle-blower, such as turning to her or others in the government, instead of releasing the information and fleeing to Russia. And Americans already see far more intrusion into their lives from commercial sources, she said, noting that her daughter emailed a contractor about a bathroom faucet and then started receiving messages from other contractors.

“There are all kinds of things that are going on. And for some reason, the fear of our government for a bona fide reason, which is to prevent a terrorist attack, raising this kind of concern, when there are only 22 people in our country who have access to this database and every one of them is vetted,” she said.

She defended the oversight of the program, rejecting a suggestion recently made by President Obama that the data be held by telecommunications firms, as well as legislation introduced Tuesday by Sen. John McCain (R-Ariz.) for a special committee to investigate the NSA. That, she said, would duplicate existing panels.

“That’s what we do,” Feinstein said in an interview.

At the dinner, Feinstein, recalling a recent emotional visit to the 9/11 memorial in New York, said she had only one goal: “I am really dedicated to doing whatever I can, within the law, to see that this never happens again in this country,” she said to applause.

Feinstein spoke to about 120 people dining on sea bass and risotto, a mix of the political (former Los Angeles City Councilwoman Roz Wyman, former U.S. Commerce Secretary Mickey Kantor and congressional candidate Wendy Greuel) and Hollywood (studio officials, actress Morgan Fairchild).

The speech largely focused on foreign policy. Feinstein said the nation must have a “major” counter-terrorism effort in Syria and, along with other nations, must take action against the government of Syrian President Bashar Assad.

“How we do this, I can’t say,” she said. “I don’t think we can continue to sit and see what’s happening in Syria.”

Feinstein singled out Secretary of State John F. Kerry for praise.

“I don’t know anyone who has been more mission-directed as secretary of State than John Kerry,” she said.

In the interview, she said that was not a comparison to former Secretary of State and potential presidential candidate Hillary Rodham Clinton.

“I think he’s different,” Feinstein said. “Hillary did a great deal, I think, in carrying the American mission abroad in the most positive way -- to women, to minorities, to everybody. I think she’s just wonderful. What John has been doing is concentrating on specifics and going after them.... He’s got his hands on and he is indefatigable.”

Feinstein’s remarks turned to California when she was asked by dinner attendees about the drought. She ribbed Gov. Jerry Brown, a longtime friend whose marriage she officiated, for not taking a stance on a water bond on the November ballot. (Some believe he does not want to put a bond measure on the November ballot – when he will be up for reelection -- for political reasons.)

“I am of the view there ought to be a bond issue and I’ve talked to the governor about it, and he’s been, I don’t know where he stands on it,” Feinstein said, prompting smirks and laughter in the crowd. She started chuckling, and said, “But this is the time if you’re going to do a bond issue ... you’ve got the opportunity and you’ve got the timing.”

Sparked by former National Security Agency contractor Edward Snowden's ongoing leaks about the organization's extensive surveillance practices, the once-secret tactics of the U.S. government became known worldwide, bringing the debate over privacy to the forefront in 2013. Read more: 2013:...

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